Nomenclature of Elements with Atomic Numbers: Nomenclature, Numerical Roots & Sample Questions

The IUPAC system assigns systematic names to superheavy elements based on their atomic numbers, using numerical roots to construct names and symbols. These temporary names are used until a permanent name is approved, often honoring scientists, places, or mythological figures. The system employs Latin and Greek numerical roots to represent the digits of the atomic number, followed by the suffix -ium to align with traditional element naming conventions. NCERT solutions includes answers to the questions related to this topic. 

The following table lists the numerical roots used to form systematic names:

Naming Procedure

To name an element with atomic number  :

1. Break the atomic number into its individual digits.

2. Assign the corresponding numerical root to each digit, from left to right.

3. Combine the roots into a single word, omitting the last letter of intermediate roots if needed for smooth pronunciation.

4.  Add the suffix -ium to indicate it is an element.

Table 1: Numerical Roots for Systematic Element Names

5. For the symbol, use the first letter of each root (capitalized for the first letter, lowercase for others).

• Element 101:
• Digits: $\mathrm{1,0},1$ .
• Roots: un, nil, un.
• Name: Un + nil + un + ium = unnilunium.
• Symbol: $\mathrm{U}+\mathrm{n}+\mathrm{u}=$ Unu.
• Permanent name: Mendelevium (Md), after Dmitri Mendeleev.
• Element 112:
• Digits: 1, 1, 2.
• Roots: un, un, bi.
• Name: Un + un + bi + ium = ununbium.
• Symbol: $\mathrm{U}+\mathrm{u}+\mathrm{b}=$ Uub
• Permanent name: Copernicium (Cn), after Nicolaus Copernicus.
• Element 118:
• Digits: 1, 1, 8.
• Roots: un, un, oct.
• Name: Un + un + oct + ium = ununoctium.
• Symbol: U + u + o = Uuo.
• Permanent name: Oganesson (Og), after Yuri Oganessian.

Question: What is the systematic name and symbol for the element with atomic number 104? Solution:

• Digits: $\mathrm{1,0},4$ .
• Roots: un, nil, quad.
• Name: Un + nil + quad + ium = unnilquadium.
• Symbol: $\mathrm{U}+\mathrm{n}+\mathrm{q}=$ Unq.

Answer: Name: unnilquadium; Symbol: Unq. (Permanent name: Rutherfordium, Rf) (NCERT, p. 13.6).

Once an elements discovery is verified, usually by international laboratories, IUPAC assigns a permanent name proposed by the discoverers. These names often reflect:

• Scientists: e.g., Mendelevium (Md, Z=101) for Mendeleev.
• Places: e.g., Californium (Cf, Z=98) for California.
• Mythological Figures: e.g., Thorium (Th, Z=90) for Thor.

Properties or Laboratories: e.g., Oganesson (Og, Z=118) for Yuri Oganessian, a key figure in superheavy element research. Until officially named, the systematic name (e.g., ununpentium for $Z=115$ ) is used. For example, element 115 was called ununpentium before being named Moscovium (Mc) in 2016 (NCERT, p. 13.6).

The following table lists selected superheavy elements, their systematic names, symbols, and permanent names:

Significance for JEE Main

For JEE Main, understanding the nomenclature of elements with $Z>100$ is crucial, as questions may test:

1. Deriving systematic names and symbols from atomic numbers.

2. Recalling permanent names of transuranic elements.

3. Understanding the IUPAC naming system and its application to superheavy elements.

Table 2: Nomenclature of Elements with

Here is a sample question for JEE Main but remember that such questions can be asked in NEET and CUET as well:

Question: What is the systematic name for the element with atomic number 123?

Solution:

• Digits: 1, 2, 3.
• Roots: un, bi, tri.
• Name: Un + bi + tri + ium = unbitrium.
• Symbol: $\mathrm{U}+\mathrm{b}+\mathrm{t}=\mathrm{U}\mathrm{b}\mathrm{t}$ .

Answer: Name: unbitrium; Symbol: Ubt (NCERT, p. 13.6).